Occurrence of Two Generations of Nudibranchs. 15 
Alder and Hancock make no mention of bilamellata in captivity, but of 
pilosa they say that it is difficult to keep owing to its propensity of crawling 
out of the water. This propensity was exhibited by all our forms, but, 
nevertheless, the larger forms spawned in captivity, the process of ovi-position 
was observed, and some of the spawn was hatched. 
Thus our specimens appear to combine the characters of bilamellata and 
pilosa, sharing features of general conformation with both of them, whilst 
they resemble the former as regards their branchial and masticatory organs 
and their double breeding period, but the latter in the size and disposition of 
their spawn spirals. 
(Issued separately, 14th September 1916.) 
